Train control



W. K. HOWE TRAIN CONTROL June 11, 1929.

Filed Nov. 17, 1924 A TTORNEY speed Patented June 11, 1929,

UNITED @TATES tries.

WINTHROP K. HOWE, 023. ROCHESTER, NEW/V YORK, ASSIGNOR TO GENERAL RAIL-W SIGNAL COMPANY, OF ROCHESTER, NEW YORK.

TRAIN oonrnoL.

Application filed November 17,1924 Serial No. 750,374.

This invention relates to automatic train control systems, and more particularly to a system incorporating means for automatically detecting failure of the drivingmechanism of the car-carried apparatus connected to the car wheels.

In the type of train control system commonly known as the train speed control or permissive speed system, some suitable speed responsive device is included in the carcarried equipment, and is suitably driven from the axles of the vehicle in accordance with the progress of the vehicle along the trackway. If the driving mechanism of this responsive device should become broken or disconnected, the device would indicate a zero speed, and no restrictive brake application would be imposed under any traiiic conditions, with the result that the train control system would become ineffective.

WVith the above and other considerations in mind, it is proposed in accordance with the present invention to provide means for checking the operation of the driving mecha nism for the car carried speed responsive device, and n'lorespeciiically, to provide means for imposing an automatic brake application if the speed responsive device is not in operation within a given time interval after an influence corresponding to caution or dangertrafiic conditions is received. Other objects, characteristics and advantageous features of the present invention will become apparent as the description thereof progresses.

In the drawings, Figure 1 represents a simplified type of train speed control system embodyingthe checking device of the present invention; and

Fig. 2 represents a modification of the starting circuit used in the system shown in l igure l.

is understood that the checking appafor the speed responsive device com 1 ing the'present invention might be used in connection with any form of automatic train control system of the permissive speed type, but for the'purpose of illustration, an extremely simple form of permissive speed system embodying the well known continuous inductive method of influence communication has been shown. As train control sy these relays being energized by the track batteries l which are connected across the track rails at the exit ends of the blocks, reference being had to the normal directionof traffic as indicated by the arrow. The track relays 3 operate the movable contact fingers 5 and 6 which control a circuit for impressingan alternating control current across the track rails at the entrance end of each block from the transmission line 7, this circuit including the transformers 8 and 9 as clearly shown. a

The usual wayside semaphore signals Z have been shown in a conventional manner at the entrance end of each block, it being understood that any other type of wayside signals may be used- .7 i

It is obvious that if a train is located in a given block its wheels and axles will shunt the track battery 4 and the secondary winding of the transformer 9. causing the track relay 3 associated with this block, to be deenergized and the control current to be cut off in the track rails behind the train. The de-energization of the track relay will cause the control current to be cut oil from the track rails in the block next in the rear of the given block by the retraction of the contact lingers 5 and 6 of this relay.

A railway vehicle has been conventionally represented in the block H by the wheels and axles '10, this vehicle being provided with the usual inductive receiving coils l1 mounted in inductive relation to. the track rails 'l, in front of the leading axle of the vehicle. These receiving coils 11 are connected in such a manner that currents induced therein by the control current flowing in opposite directions in the two track railswill be additive. The receiving coils 11 are connected to the input circuit of a suitable amplifier, preferably of the audion tube type, which has been conventionally represented at A; the output of this amplifier being connected to the main relay MR as shown. This main relay MR is provided with two movable contact fingers 12 and 13, which contacts are included in control circuits as hereinafter described.

Referring now to the car-carried equipment, a drive shaft 14 is provided and is geared or otherwise suitably driven from an axle of the vehicle. This shaft 14; carries a worm 15 and a speed responsive device. The speed responsive device may take any suitable form, but in the embodiment chosen for the purpose of illustration, a simplified speed responsive device has been shown, taking the form of the centrifuge Gr. This cen trifuge comprises a fixed collar 16 and a movable collar 17 on the shaft 14, urged apart by the spring 20; the collar 1-? being drawn downwardly as the speed of rotation of the shaft 14 increases by a centrifugal force acting on the weights 19 which are connected to the collars 16 and 17 by the links 18. The collar 17 engages an arm 21 fixedly secured to a speed shaft 22 as clearly shown, so that the shaft 22 rocked in proportion to the speed at which the vehicle is traveling. It should be noted that the worm 15 and the fixed collar 16 are intimately associated, being preferably made integral, so that the possi bility of a failure of the driving mechanism between the worm 15 and the centrifuge G is very remote.

The worm 15 operates a distance shaft through a gear 2st, a shaft 25 and a gear train 26, carried by magnetically operated arm 27 as shown. The arm 27 is held in the disengaged position by means of the cam starter magnet CS, and when this magnet is de-energized the spring 28 places the arm 27 in a position such that the end gear 29 of the gear train 26 engages a mutilated gear 80 which is secured to the distance shaft 23. The distance shaft 23 is returned to its normal position upon the disengagement of the gears 2) and 30 by means of a spring 31.

Suitable means are provided for closing a circuit in response to the initial movement of the distance shaft 23, and in the embodiment shown, a distance cam 32 is provided on the shaft 23 and operates a pair of resilient contact fingers 3a which are biased to their open position, the cam 32 being designed to close these contact fingers as soon as the distance shaft 23 starts to rotate.

The vehicle speed may be controlled in any suitable manner, but in the system shown, means are provided for controlling the vehicle speed in accordance with the distance of travel from a point at which a restrictive impulse is received from the trackway; it being understood that any one of a number of well known train speed control means might be used. The speed-distance or permissive speed feature provided by means of a permissive speed cam 33- secured to the shaft 23 and acting to operate one end of a floating lever 35, the other end of which is moved by an arm 36 fixedly secured to the speed shaft 22. It is evident that the movement of an intermediate point on the floating leveri-lo is proportional to a function of the vehicle speed and its distance of travel from the point at which the distance shaft 23 is initiated. The floating lever operates a contact sector 37 through a link 2 8, this contact sector 3'? being biased by a spring 39. The sector 37 operates the resilient contact fingers it), which are normally biasedto their open position, and it is evident that as the vehicle speed increases, the contact sector 87 will be swung in a clockwise direction by the arm 36, the floating lever 35 and the link 38, causing the Contact fingers 40 to open at some predetermined speed depending on the posit-ion of the permissive speed cam and the construction of the contact sector 37.

A check relay GR is provided and is of a suitable slow acting type, that is, once energized, it will not retract its contact linger a l for a gven ieriod of time after its deenergization. This slow acting feature may be accomplished by providing a copper sleeve around the relay core to sustain the flux therein, or by a dash pot, or other suitable mechanical means.

A starting relay SE of any suitable type is provided, its energizing circuit including a push button PB as shown. This starting relay 15 of the slow drop-away type, this feature being secured by a dash pot and a flexible arm combination.

The automatic control of the brakes of the vehicle may be effected in any suitable manner and by means of any suitable automatic brake control device. As the automatic initi' ation of a brake application is usually effected by means of some suitable air valve, an electropneumatic valve EPV has been shown in the drawings, it being understood that this eleetro-pneumatic valve acts in some suitable manner to initiate a brake application upon the de-energization of a circuit through its windings.

Operation.All of the apparatus in. the drawings has been shown in its normal operating cmidition, that is, the positions of the various devices are such as is assumed with a train running at a speed below the maximum but above the minimruu permissive limit, and under clear traflic conditions ahead. The letters B and C have been used to indicate the opposite poles of a suitable source of energy, preferably a storage battery.

Referring briefly to the operation of the simplified train control system shown, assuming a train to be proceeding under clear traffic conditions, that is, with no other train in the block in which it is located or in the through wire 47, contact finger 41 and frontcontact of the check relay CR, wires 49 and 51, contact fingers 40 of the contact sector 37, Wires 52, contact finger 44 and'back contact of the push button PB and wire 53 through the Winding of the electro-pnew matic valve EPV to the battery terminal 0. The cam starter magnet CS is also main tained energizedthrough contact finger 13 of the main relay MR and a circuit which is obvious from the drawings. lVith the cam start-er magnet CS energized, the distance shaft 23 will be maintained in its normal position, as shown, by the spring 31.

Assume now that a train equipped with the system shown enters a block in which caution or danger trafiic conditions exist, that is, a block in which another train is locat-ed or the first block in the rear of such occupied block. Under these conditions, the

' train control current is cut off from the track rails and the receiving coils 11 do not have currents induced therein, causing the.

de-energization of the main relay and the consequent retraction of its contact fingers 12 and '13. The retraction of the contact finger 13 breaks the energizing circuit to the cam starter magnet CS, thus allowing the spring 28 to engage the gear train 26 and the mutilated gear 30 and the distance shaft 23 is thereby rotated. The retraction of the contact finger 12 of the main relay MR deenergizes the check relay CR, which, after a period of time, retracts its contact finger 41; but before this contact finger 41 has been retracted, the distance cam 32 will have closed its contact fingers 34, shunting the contact finger 41 through the wires 48 and 50, so that the de-energization of the cheek relay CR has no elf-ect under these conditions.

The distance shaft 23 is now rotated in accordance with the progress of the vehicle, and the permissive speed cam 33 moves the upper end of the floating lever 35 to the left, so that the train speed must be reduced to bring the lower end of the lever 35 to the right in order to prevent the opening of the contact finger of the contact sector 37 and a consequent de-energization of the electro-pneumatic valve EPV which would cause an automatic brake application.

The distance shaft 23 continues to rotate until the mutilated portion of the gear 30 is opposite the gear 29, and at this point a minimum speed restriction is imposed by the cam 33 and the train may proceed at this limited speed only until the main relay MB is again energized in response to more favorable traffic conditions.

Referring now more particularly to the operation of the check for the driving mechanism which comprises the present inven-.

tion, assume that the driving mechanism for the shaft 14 becomes broken or disengaged from the axle of the vehicle or that for any other reason the cam shaft 23 fails to move when it should. caution or danger block with the drive shaft disengaged, the main relay MR will be deenergized, causing a de-energization of the check relay CR and the cam starter magnet CS as described above. 23 will not be rotated because ofthe failure of the driving mechanism, and for this reason the contact fingers 34 of the distancecam 32 will remainopen. After a given time interval, the check relay CRwill retract its contact finger 41, breaking the energizing circuit to the electro-pneumatic valve EPV traced above, and causing an automatic brake application bringing the train to a WVh'en the train enters a The distance shaft stop- The engineer may now repair the 1 driving mechanism or, preferably, render the automatic brake control apparatus 'lIlactive by the operation of a suitable cut-out device, such as a switch, which may be provided in connection'with the automatic train control system for connecting the wire 53 with the batteryterminalxB and so maintaining the electro-pneumatic valve energized; this cutout device preferablybeing protected against unauthorized use by asealed casing or other suitablemeans.

In a 7 continuous inductive train control system, a train may cometo a stop under clear trafiic conditions, and While at a stop, the

traflic conditions may change to caution or danger by reason of the entrance of a train, the breaking of a track rail, the opening of a switch, or other hazards in the block in which the stopped train is located. or in the first block in advance thereof. Under these conditions, the main relay MB is de-energized and retracts its contact fingers 12 and 1.3, deenergizing the check relay CR and the cam starter magnet CS. After a time interval, the check relay CR drops its contact finger 41, but, as the train is not moving, the contact fingers of the distance cam 32 have not been closed and the circuit to the electro-pneumatic valve is therefore broken, causing an automatic brake application and holding the train stationary. In order that the train may be released from this automatic brake application and may proceed, a separate manual meansis provided for energizing the check relay CRwhich means is protected against misuse as hereinafter described. The push button PB is depressed by the engineer causlay SR attracts its contact finger 4L2, closing an energizing circuit for the check relay CR through wlre 46 as clearly shown, the push button being maintained depressed until the check relay CR has attracted its contact finger ll, after which'the push button PB is released. An energizing circuit for the electropneumatic valve EPV is now completed through the contact finger 41 of the check relay CR, which circuit has been traced, and this circuit is maintained for a time interval equal to the sum of the drop away periods of the two relays CR and SR, both of which relays are slow acting as hereinbefore described. This time interval is arranged to be long enough to energize the electro-pneumatic valve, to permitthe engineer to release the brakes from the automatic brake application and to allow the train to get in motion. As soon as the train is in motion, the distance cam 32 will close its contact fingers 34, shunt ing the contact finger 410i": the check relay CR and completing an energizing circuit for the electro-pneumatic valve EPV. The train may now proceed under the control of the permissive speed cam 3321s described above.

It should be noted that the engineer may not abuse the use of the starting relay SR by fastening or holding the push button PB in its depressed condition, as this push button is provided with a contact finger 4A which is included in the energizing circuit for the electro-pneumatic valve, this contact being open when the push button is depressed and so maintaining the electro-pneumatic valve de-energized until the push button is released.

In Figure 2, an alternative scheme has been shown for re-energizing the check relay CR and so allowing the train to proceed after this relay has been de-energized by reason of a change to danger or caution trafiic condition while the train is at a stop. In this modification, the starting relay SR and the push button PB are omitted, and an air operated switch S is provided. This switch consists of a piston 54, carried in a cylinder and op erating an insulated contact member 56 which is adapted to engage two stationary contact fingers conventionally represented by the arrows 57 and 58, when air pressure is applied to the cylinder 55. The piston 54 is returned to a position to open the contacts 56, 57 and 58 by means of a spring 59 when theair pressure in the cylinder 55 has diminished below a predetermined value. The cylinder 55 is connected by a suitable pipe 60 to theFbrake cylinder pipe of the well known ET -air brake equipment or other suitable connectlons are made so that pressure is'applied to the cylinder 55 and the contacts 56, 57 and 58 ar closed only when the brakes have been applied on the engine and tender. The contacts 57 and 58 are connected to the check relay and to the battery terminal B as shown, so that the check relay GR is energized through these contacts when the engine and tender brakes are applied. It the engine and tender brakes are maintained applied until the instant which the train is to be started, the check relay OR is maintained energized While the train is stationary even though the main relay MR is ale-energized. If, however, the engine and tender brakes have been released, the engineer will apply these brakes just before releasing all of the brakes to start the train. As the train starts, the brakes are released, and the circuit through the air switch S is broken, de-energizing the check relay CR, but before the check relay has retracted its contact finger 41, the distancecam 32 closes its contact fingers 34:, so maintaining the circuit to the electropneumatic valve closed, andthe train may proceed under the restriction of the permissive speed cam 33 as described above. It the train exceeds the permissive speed limit set up by the cam 33 while traveling under caution or danger control, an automatic brake application results as described above, and this application causes the air switch S to close its contacts 56, 57 and 58, re-energizing the check relay CR. As the contacts 34 of the distance cam 32 are closed while the train is under danger or caution control, this rethe de-energization of the main relay MR,

and,ras the contacts 34 of the distance cam 32 do not close, the electro-pneumatic valve EPV is deenergized by the retraction of the contact finger ll of the check relay. The deenergization of the electro-pneumatic valve EPV causes an automatic brake application, and as the air is admitted to the brake cylinder pipe of the well known ET equipment, the air switch S connected to this pipe is closed, re-energizing the check relay CB and the electro-pneumatic valve EPV, thus permitting the release of the brakes. As soon as the brakes are released, however, the air switch S will re-open, tie-energizing the electro-pneumatic valve, thus causing another automatic brake application. It is thus evident that with the driving mechanism broken or otherwise disengaged, an automatic brake application will result under caution or danger conditions, and that although this brake application can be subsequently released, a second automatic brake application will follow if the brakes are released, and so on, thus imposing successive automatic. brake applications and, it the train be not stopped, at least limiting the progress of the train to a safe speed. As stated, de-energization of EPV produces an automatic brake application, which in turn, through switch S, re-energizes relay OR to cause energization of E'PV and permit the engineer to release the brakes and to retain the brakes released until relay GR has released and the consequent de-energization of EPV has caused a new automatic brake application.

It is obvious that in the modified system shown in Figure 2, no protection against misuse is needed, it being assumed that a safe control is imposed if the brakes are applied, and for this reason the energizing circuit for the electro-pneumatic valve EPV in a system employing this modification would be connected directly to the contact finger 40 of the contact sector 37 through the wire 52' (PB being omitted).

As the drive mechanism checking device comprising the present invention has been described in a rather specific manner and in connection with one specifictype of train control system, it should be clearly understood that this device may be modified or combined with other equipment, and further that this device would be employed with any suitable type of permissive speed train control s stem without departing from the spirit of t e present invention as defined by the appended claims.

\Vhat it is desired to secure by Letters Patent is 1. In an automatic train control system, vehicle carried control means including elements adapted to be driven in accordance with the progress of the vehicle, means for setting said control means in operation, in response to an influence corresponding to unfavorable traflic conditions ahead, means for imposing an automatic brake application if said driven elements are not in operation within a predetermined period of time after said influence is received, and means effective only if the brakes are applied, for preventing said automatic brake application.

2. In an automatic train control system,

vehicle carried apparatus comprising a control means responsive to influences corresponding to tratlic conditions ahead, a restrlctive speed device having an element drlven in accordance with the motion of the vehicle, said restrictive speed device being initiated by said control means under unfavorable traffic conditions ahead, means for causing an automatic brake application if said restrlctive speed device is not in operation w thin a predetermined period of tlmeafter said control means has received an influence corresponding to unfavorable traffic conditions ahead, and means for temporarily releasing the vehicle from said automatic brake application.

8. In an automatic train control system, vehicle carried control means responsive to influences corresponding to traific conditions ahead, a restrictive speed device having a dis tance element adapted to be driven at times in accordance with the motion of the vehicle,

said distance element being initiated by said control means under unfavorable traflic conditions ahead, means for causing a brake application ifsaid distance element has not been initiated within a predetermined period of time after the reception of an influence corresponding to unfavorable trafiic conditions ahead, and manually operablemeans for permitting the release of said automatic brake application for a limited period of time.

4. In an automatic train control system, vehicle carried brake control apparatus comprising a brake applying device, a restrictive speed device including an element driven at times in accordance with the progress of the vehicle, a mainrelay controlled in response to influences corresponding to traffic conditions ahead, means controlled by the de-energization of said main relay for initiating said driven element and controlling said brake applying device by said restrictive speed device under unfavorable trafiic conditions, a control relay actuated'by said main relay and acting to operate said brake applying device if said driven element has not been initiated within a predetermined period of time after the de-energization of said main relay, and means for temporarily preventin -the operation of said brake applyingdea vice by said control relay. 7 I

5. In an automatic train control system, vehicle carried brake control apparatus comprising a brake applying-device, a restrictive speed device including anelement driven at times in accordance withthe progress of the vehicle, said restrictive speed device normally controlling said brake applymg device, a main relay controlled ln response to influences corresponding to tratiic conditions ahead, means controlled by said main relay for initiating said driven element of said r.e

strictive speed device under unfavorable traffic conditions ahead, means for actuating said brake applying device independently of said restrictivespeed device if said driven element does not operate in response to the control of said main relay, and manually actuable means for temporarily placing said brake ap plying device under the control of said restrictive speed'device.

6. In an automatic train control system, vehicle carried brake control apparatus com prising a brake applying'device, a restrictive speed device including an element driven at times in accordance with the progress of the vehicle and normally controlling said brake applying device, a control means for connecting the driven element of saidrestrictive speed device to a driving member in response to control influences corresponding to unfavorable traiiic conditions ahead, meansior causing said brake applying device to operate independently of said restrictive speed device if said driven element is not initiated in response to the operation of said control means, and means, actuable only ii thevehicle brakes are applied, to return the control of said brake applying device to said restrictive speed device for a limited period of time.

7. In an automatic train control system, vehicle carried apparatus comprising a restrictive speed device including an element adapted to be driven in accordance with the progress of a Vehicle and acting to i1npose increasingly restrictive speed limits when initiated; a control device for initiating the operation of said driven element in response to influences corresponding to unfavorable traiiic conditions ahead, a relay controlled by said control device and acting to impose an automatic brake application it said driven element does not ope ate in response to the operation of said control device, and additional means for operating said relay to release said automatic brake application tor a limited period of time if the vehicle brakes are applied.

8. In an automatic train control system, vehicle carried apparatus comprising a restrictive speed device including an element adapted to be driven in accordance with the progress of a vehicle and acting to impose increasingly restrictive speed limits when initiated; a main relay for initiating the operation of said driven element in response to influences inductively received from the trackway and corresponding to unfavorable trafic conditions ahead, a control relay operated by said main relay and acting to impose an automatic brake application if said driven ele ment does not operate inresponse to said main relay and means including an air switch for preventing said automatic brake application it the vehicle brakes are applied and for a limited period of time after the brakes are released 9. In an automatic train control system, vehicle carried control apparatus comprising a main relay controlled by influences corresponding to traflic conditions ahead, a control relay controlled by said main relay, a restrictive speed device driven in accordance with the motion of the vehicle under unfavorable tratiic conditions ahead, a normally energized brake applying device adapted to control the vehicle brakes when deenergized, circuits for energizing said brake applying device having a common portion including contacts operated by said restrictive speed device in series with parallel portions one of which includes a contact of said control relay, and the other of which includes contacts closed only when said restrictive speed device is being driven, and means for temporarily energizing said control relay when said main relay is de-energized.

I i 10. In an automatic train control system,

vehicle carried control apparatus comprising a main relay controlled by influences corresponding to traffic conditions ahead, and deenergized under unfavorable trafiic conditions, a slow acting control relay controlled by said main relay and arranged to open its contacts a predetermined time after said main relay is tie-energized,arestrictive speed device initiated by the de-energization of said main relay and having an element driven from the vehicle wheels when initiated, a normally energized brake applying device adapted to apply the vehicle brakes when (lo-energized, means for controlling the encrgization of said brake applying device in accordance with the operation of said restrictive speed device, further means including contacts of said control relay for causing the de-energization of said brake applying device independently of said restr1ct1ve speed device if said driven element of said restrictive speed device is not initiated a predetermined time after said main relay is tie-energized, and means for energizing said control relay to re-energize said brake applying device if the vehicle brakes are applied.

11. In an automatic train control system, vehicle carried brake control apparatus comprising a brake applying device, a restrictive speed deviceincluding an element driven at times in accordance with theprogress of the vehicle, said restrictive speed device normally controlling vsa1d brake applying device, a.

main relay controlled in response to influences corresponding to traffic conditions ahead, means'controlled by said main relay for initiating .said driven element of said restrictive speed device under unfavorable trailic conditions ahead, means for actuating said brake applying device independently of said restrictive speed device if said driven element does not operate in response to the control oi sain main relay, and manually actuable means for temporarily placing said brake applying device under the sole control of said restrictive speed device.

12. In a train control system, carcarried apparatus including, a brake applying device, traific controlled means for initiating said device, a restrictive speed device controlled at times in accordance with the progress of the tram and effective at times to in- 1t1ate said brake applying dev1ce, and an element driven in accordance with the distance ing a shunt around said traffic controlled means for preventing said initiation of said 'device during train movement, only if its drive means is in operative condition.

14. In a train control system, car-carried 5 apparatus including, a brake applying device, trafiic controlled means for initiating said device, an element driven in accordance with the amount of movement of the train for preventing said initiation of said device during train movement, only if its drive means is in operative condition, and means for temporarily preventing initiation of the brake applying device when said drive means is inoperatve.

15. In a train control system, car-carried apparatus including, a brake applying device, traffic controlled means for initiating said device, an element driven in accordance with the amount of movement of the train for closing a shunt around said trafiic controlled means for preventing said initiation of said device during train movement, only if its drive means is in operative condition, and means for temporarily preventing initiation of the brake applying device when said drive means is inoperative.

In testimony whereof I aflix my signature.

WINTHROP K. HOWE. 

